Hydrological Modelling in Data-Sparse Regions: Impacts of Land Use and Climate Change on the Hydrological Cycle in the Lake Kivu Basin

The Lake Kivu catchment, in the African Great Lakes Region, faces significant hydrological challenges due to unsustainable Land Use Land Cover Changes (LULCC) and climate change. Steep slopes, abundant rainfall, and human-induced activities exacerbate environmental disasters, including floods, landslides, and soil erosion, particularly in flood-prone areas such as the Sebeya River catchment. Over the past decades, the catchment has witnessed notable LULCC, including a decline in forest cover from 26.6% to 18.7% and an expansion of agricultural land from 27.7% to 43% between 1990 and 2000. Subsequent forest recovery to 24.8% by 2020 highlights the impact of Rwanda’s sustainable development initiatives. Rapid population growth and urbanization continue to alter hydrological patterns, increasing surface runoff and reducing groundwater recharge. Climate change projections suggest an intensification of extreme precipitation events, escalating flood risks in the region.

This study aims to enhance understanding of the interplay between LULCC, climate change, and hydrological dynamics in the Lake Kivu basin by addressing critical gaps in streamflow data and applying advanced hydrological modelling techniques. A robust stochastic methodology was developed to fill missing streamflow data, enabling accurate analysis of historical trends and future scenarios. The mesoscale hydrological model (mHM) was employed to evaluate historical impacts of LULCC and to simulate future hydrological responses under various LULC and climate scenarios, integrating data from Global Climate Models (GCMs) and Representative Concentration Pathways (RCPs).

Our findings underscore the importance of addressing data scarcity in hydrological research, particularly in data-sparse regions. This research contributes to sustainable land and water management by providing actionable insights into mitigating hydrological disasters and building resilience against future climate extremes.